"DRL committed an act of infringement by filing an ANDA (Abbreviated New Drug Application) with a Paragraph IV Certification that seeks FDA-marketing approval for DRL generic versions of AbbVie's paricalcitol injection products prior to expiration of the patents-in-suit," according to a petition filed by AbbVie along with Wisconsin Alumni Research Foundation in the US District Court for the District of Delaware.

The US Drug maker requested the court to pass an order to restrain DRL from commercially manufacturing, using, offering for sale, selling, marketing, distributing, or importing DRL's generic paricalcitol injectable products prior to the expiration of said patents.

Dr Reddy's filed an ANDA with the US Food and Drug Administration, seeking approval to sell a generic copy of US drug maker's Zemplar injectable products in 2 microgram/ml and 5 microgram/ml formulations, prior to the expiration of the patents owned by and exclusively licensed to the complainants, the petition said.

Dr Reddy's Lab refused to comment on the issue.

Zemplar (Paricalcitol) is a drug used for the prevention and treatment of secondary hyperparathyroidism (excessive secretion of parathyroid hormone) associated with chronic renal failure.

AbbVie, in its annual report 2012, said it cloaked USD 383 million from Zemplar sales including USD 230 from the US.

Two patents (799 and 758) originally belonged to Abbott and subsequently transferred to AbbVie. These two patents will expire on April 8, 2018.

Wisconsin Alumni research foundation holds the rights for patent no. 815, which will expire on July 13, 215, AbbVie informed the court in the petition.

On or about May 20, 2013, AbbVie and WARF received letters dated May 17, 2013, from DRL notifying that the India drug maker had filed an ANDA containing a Paragraph IV Certification for paricalcitol injection.

The letter also stated that, in DRL's opinion, the patents-in-suit are invalid, unenforceable, or will not be infringed by the commercial manufacture, use, or sale of the generic paricalcitol injection products, the petitioners said.

"DRL has committed and will commit acts of infringement of the patents-in-suit that create a justiciable case or controversy between plaintiffs and DRL," the petitioners alleged.